


Demonstrations

by OnceUponACaskett



Series: 2014 Castle Summer Kink Meme [9]
Category: Castle
Genre: Castle Kink Meme, Caught having Sex, F/M, Kink Meme, Multi, Slight Incest, Slight Parent/Child Incest, Teenager, Voyeurism, son - Freeform
Language: English
Status: Completed
Published: 2014-07-19
Updated: 2014-07-19
Packaged: 2018-02-09 12:09:44
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,602
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1982448
Author URL: https://archiveofourown.org/users/OnceUponACaskett/pseuds/OnceUponACaskett
Summary: <blockquote class="userstuff">
              <p>I marked underage just in case anyone wasn't okay with a 16 year old. Fill for the 2014 Summer Hiatus Kink Meme. Castle and Beckett's son catches them having sex and right after, Castle teaches his kid how to give a woman pleasure in bed.</p>
            </blockquote>





	Demonstrations

**Author's Note:**

> Prompt: Caskett's teenage son catches his parents having sex. When the boy is caught watching them, Castle gives his son advice and acts it out for him. Your choice if he then displays what he's learned.
> 
> The archive warning says underage, but it's really not. The OC is 16 years old, but I put the warning just in case anyone got too touchy about it.

James sighed and walked through the front door of his home. He was supposed to have been at his friend’s house, studying for the big exam tomorrow, but his so-called friend blew him off to go hang out with his girlfriend. It totally sucked that he’d gone all the way to David’s house and then had to come back almost immediately.

Hearing a strange noise to his right, the teen looked in that direction and noticed the door to his dad’s office was ajar. Frowning, he cautiously walked over to it and could hear even more muffled sounds. Pushing the door open, James glanced around the small room and saw that it was empty. However, the door to his parent’s bedroom was cracked and that’s exactly where the noises were originating from.

“Castle,” he heard a woman’s voice gasp. “Fuck me harder!” And that wasn’t just any woman’s voice; that was his mom.

 _Oh shit, my parents are totally having sex right now,_ the teen thought to himself. His first instinct was to turn tail, hide in his room, and shove earplugs in his ears. That thought, however, was gone just as fast as it had come, replaced instead by another crazy idea. Quietly stepping towards the bedroom door, James lightly pressed it farther open, just enough so that he would be able to see the activities going on.

His parents were lying sideways across the bed, parallel to the headboard, which was great for James because he could see _everything._ His dad drove repeatedly into his mom while she moaned and writhed beneath him.

Castle swooped down and captured a nipple in his mouth, rolling his tongue harshly over the small bud, his rhythm never faltering once.

James could feel his pants rapidly getting tighter and more constraining by the minute. The sixteen-year-old knew that his parents weren’t exactly bad-looking; they were actually quite attractive for their ages, a fact that his many friends—both male and female—never seemed to let him forget. Bringing a hand down to the front of his jeans, the boy cupped his growing erection and squeezed lightly, biting his lip to hold back a groan that threatened to escape.

He saw his mom wrap her long legs around his dad’s waist, limiting his movement. Castle chose to grind his pelvis hard into Kate’s instead of adjusting her grip on him. One of her hands fisted in the sheets as her head tilted to the side. Her eyes widened when she saw her teenage son standing in the light that was pouring in from the partially open door.

“Castle!” she said urgently. “Castle, stop!”

Her husband looked confused at her sudden change in mood. When he followed the direction her eyes were staring in, he smirked.

“C’mere, son,” he said to James, gesturing for the boy to enter the room. Complying, James stood awkwardly by the door, his eyes never leaving his mother’s nude form.

It wasn’t that he’d never seen a naked girl before; he _was_ a teenage boy after all and had watched his fair share of porn. But he’d never seen a girl naked in person and it was completely different from seeing one on the internet.

"Babe, what’re you doing?” Kate asked her husband.

“He’s obviously just curious,” Castle answered. “And besides, he’s sixteen and I think it’s time I give him a few pointers on how to treat a woman in bed. What d’you say, James? You wanna be able to impress the first girl you have sex with?”

James nodded eagerly. A couple of his friends had already lost their virginities and—in the confidentiality that is “the guy code”—they’d told him that their girlfriends were less than impressed with their performances. They either shot too soon or couldn’t give their girls an orgasm. James wanted to be different. He wanted his first time to be different in that he wanted to give the girl he was with a decent amount of pleasure. What better way than to gain some knowledge and experience from his former-page six playboy dad?

Castle glanced down at his wife and asked, “You alright with this? If not, we can just forget it.”

Kate sighed and smiled up at him. “Go ahead: do your thing, Castle.”

The writer grinned and then looked at his son. “And that brings us to rule number one: always be courteous and aware of your partner’s wants and needs. If she says no to something, you don’t push her into it or try to persuade her otherwise. You drop it and move on.”

Pulling his cock out of his wife, Castle continued. “Now speaking of wants and needs, James, you gotta make sure that you spend enough time on foreplay to make her wet enough for you. If your mom and I had only just started this by the time you got here, then it’d be easier to actually show you. Instead, I want you to come over here by me.”

James moved to where Castle was. The older man put a hand to Kate’s pussy and spread her so that his son could observe.

“You see what I mean? Your mom’s been this fucking wet because I spent time kissing her neck, running my tongue over her breasts, sucking them into my mouth.” To show what he meant, Castle bent over and latched onto one of her breasts. His hand came up to fondle the other one, squeezing and rolling the taut nipple between his fingers. He was rewarded with a loud moan, signifying her approval.

Kissing down her stomach, feeling the muscles bunch and twitch underneath his touch, he halted when he reached the apex of her thighs.

“Now this is something that not every girl is gonna want you to do. Going down on someone can be seen as sometimes a more intimate act that the actual act of having sex.” Castle could tell that his son was listening to every word he said with rapt attention.

“One thing that you can and should always do, though, is fuck her with your fingers.” He ran the tips of his fingers through her, delighting in how hot and wet she was. “You should always check to see if she’s wet enough and ready for you, no matter what. She’ll appreciate it if you do this, though.” Slamming two fingers into Kate, he began a rough pace that had her hips bucking hard.

When Castle suddenly stopped and pulled out, his wife groaned and gave him a sharp look.

“What the hell, Castle?” she snapped, annoyed at the loss of the pleasurable feeling.

Ignoring her, he continued to address his son. “Unlike how I just started fucking your mom like that, you should mostly go slow for the first few times you’re with a girl. At least, until you learn what she does and doesn’t like.” Pushing a single digit back into Kate’s entrance, he said, “Start with one finger and after a little bit, add a second. Maybe even add a third if she can take it.”

Castle slid another finger into his wife and curled the digits, making Kate’s hips shoot off the mattress, her head toss back, and high-pitched whine escape her throat.

“What the fuck was that?” James asked, so alarmed by his mother’s sudden and enthusiastic reaction that he forgot to censor his words.

His dad grinned smugly at him. “That, my dear boy, was me hitting your mother’s g-spot. Some women are highly sensitive in a certain area on the front wall of their vagina and when you find it, it causes extreme amounts of pleasure for them.” To demonstrate what he meant, Castle quickly pounded his fingers into Kate, curling them with each stroke so that he struck her spot.

James watched in silent awe as his mother came very much alive under his father’s touch. Her eyes slammed shut, her head tossed from side to side on the bed while her mouth opened, her breathing turning into fast, hard panting. Her hips wouldn’t stay still as she tried to ride his hand. The teen watched as his dad placed an arm across her stomach to hold her down.

From his time spent watching porn, James could tell when someone was about to have an orgasm—and his mom was about to have a giant one. The ache in his groin was starting to get unbearable. Frankly, he didn’t know how he hadn’t dropped his pants and come all over the floor yet.

Just when he thought his mom was about to come, he saw his dad remove his hand.

 _Fuck, Mom’s not gonna be happy about that,_ he told himself. _Hell,_ I _wouldn’t be happy about that and I’m not even a fucking girl._

“Now, James, if there’s one thing you need to know about a girl’s pussy, it’s this little area right here.” Castle pointed to a small bud slightly protruding from the top of Kate’s pussy. “That’s called a clit and every woman’s got one. It’s literally full of nerve endings that make it really sensitive and you shouldn’t ignore it. A lot of women can only come if rub her clit. Fuck her all you like, but if her clit doesn’t get touched, then the odds of you giving her an orgasm have just decreased greatly.”

Plunging his fingers back into her, he set a quick pace as his thumb worked to circle his wife’s clit. Moving his free hand north, the writer grabbed her breast and kneaded it softly, watching closely as Kate moaned his name, finally being given the opportunity to come.

“Whoa,” James commented softly. Of course he’d seen the actors in his pornography come, but watching someone in real life was even more amazing. The pornstars would always exaggerate and overact to the point where some of it wasn’t even really worth viewing. But this was raw and new and he enjoyed every second of it.

"James.” His dad’s voice brought his attention back to him. Bright, blue eyes were gazing sternly at him. “However unfair it may seem to you, I want you to recognize that you are not entitled to anything when it comes to sex. If she backs out and changes her mind, even after you did all this and you have a raging hard-on, you never force her to ‘take care of it’. Do you understand me?”

“Yeah, Dad,” the teen told him seriously. “That’s not what real men do.”

Castle smiled proudly at his son. “Exactly. Now,” he turned back to Kate who was still lying on the bed, a bit dazed from her last orgasm. “When you get the all clear from her, you can go ahead and actually have sex. Unless they tell you otherwise, you should always try to go somewhat slow; give them time to adjust.”

Even though he and Kate had been together for close to twenty years, Castle wanted to show James precisely what he meant. Hovering over her, he lined himself up and sank inch by inch into his wife’s warm, welcoming entrance. He paused for a moment and said to James, “Feel free to move around and find a better spot to observe.” Pulling out and then thrusting back in, Castle began a leisure pace, keeping it slow for the time being.

Speaking to his son, he said, “Sometimes, this position isn't gonna do it for her. A slight change in the angle can create more pleasure for her.” Grabbing the backs of Kate’s knees, he brought her legs farther up, opening her wider for him.

“Fuck, Castle!” she screamed when he brushed against her front wall.

“See?” he said, his tone dripping cockiness. Out of the corner of his eye, he could see James struggling with himself. His hands were clenched into fists and he was biting his lip in a way that reminded the writer of a certain detective that was currently writhing beneath him. He saw the bulge in his son’s pants and nearly laughed.

“Go ahead, James,” he told him. “Jack off—you shouldn’t be the only not getting any satisfaction out of this.”

Now that he’d been given the okay to do it, James hastily undid his jeans, shoving them and his boxers down his legs, and wrapped a hand around his hardened shaft, twisting his wrist with every stroke.

“Everything,” his dad went on, “I taught you, you should apply here. Kissing her neck,” his lips attacked her skin, nipping lightly and running his tongue over the area to soothe the sting. “Showing her breasts some much needed attention.” He trailed his mouth down to her chest, flicking the tip of his tongue over the peak of one nipple.

His hips pistoned into her, never stopping as he drove his cock deeply into her. He released one of her legs to bring his hand down to where they were joined.

“Rubbing her clit,” he said to James, his voice a bit strained as he neared he and Kate neared their climax together. He roughly circled her clit with the pads of his fingers, feeling her clamp down around him.

“Castle!” she screamed, her nails raking down his back, leaving angry red lines in their wake.

“God, Kate,” her husband grunted into her ear as he came, spilling himself within her. He jerked his hips a couple more times before rolling off of her, his head turning to the side just in time to see his son come all over his own hand.

Gathering his strength, Castle got up from the bed and disappeared into the bathroom, returning seconds later with damp washcloths. He tossed one to James before moving to the bed.

As James wiped the stickiness from his hand and his cock, he watched with interest as his dad knelt by his mom’s side and ran the washcloth gently between her legs, cleaning her before he attended to himself.

He followed quietly behind his dad when the older man gestured to him, taking them both into the bathroom. They stood at the sink in companionable silence, rinsing out their washcloths. It was Castle that spoke first.

“One of the most important things that perhaps you should remember, James, is to wait until _you_ are ready. No matter what anyone else says or does, don’t let yourself be pressured into doing something you’re not totally comfortable with. You’re a smart kid and I have faith that you’ll know when you’re ready.”

James smiled up at him. While he had always been a mama’s boy ever since he was a baby, his dad was someone whom he knew he could trust with anything and not be unreasonable about it. His mother had a tendency to overreact when something would happen to her precious baby boy.

“Now speaking of smart,” Castle segued, “you have an exam tomorrow that you should’ve been at David’s house studying for. Since apparently that didn’t work out, get crackin’.” He gave his son a light shove out the door.

“Thanks, Dad,” James told him sincerely. “But, uh…I think Mom might need help…moving.”

Father and son glanced at the bed and saw Kate still lying in the exact same position that Castle had left her in.

“Yeah, I should probably go help her.” Castle dashed over to the bed and helped his exhausted wife shift onto a pillow and get under the covers.

Shaking his head, James went to his room. How the hell he was gonna be able to focus on his textbook right now, he had no idea.


End file.
